Orders to U.S. factories fell in February for the third time in the past four months. Meanwhile, a key category that tracks business investment plans dropped by the largest amount in two months.

The Commerce Department says factory orders fell 1.7 percent after a 1.2 percent rise in January. There was weakness in a number of categories, led by a big drop in the volatile category of commercial aircraft. Demand for machinery, computers and household appliances also fell.

Orders in a category that serves as a proxy for business investment declined 2.5 percent after a 3.3 percent increase in January.

Manufacturing has struggled for the past year as a strong dollar has cut into export sales and a big drop in oil prices has reduced investment by energy companies.